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Update recommended rustfmt config #96

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Update recommended rustfmt config #96

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73d2e1c
Update recommended rustfmt config
PoignardAzur Mar 14, 2025
342c73c
Tweak wording
PoignardAzur Mar 14, 2025
f61cbb3
Fix typo
PoignardAzur Mar 25, 2025
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15 changes: 14 additions & 1 deletion content/wiki/formatting_scheme.md
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Expand Up @@ -24,19 +24,32 @@ For those files, the formatting produced by `rustfmt` is required.
The following rustfmt config is recommended:

```toml
# LINEBENDER RUSTFMT CONFIG - v1
# LINEBENDER RUSTFMT CONFIG - v2
# Ensure lines end with \n even if the git configuration core.autocrlf is not set to true
newline_style = "Unix"

# `Foobar { foo, bar }` is more readable than `Foo { foo: foo, bar: bar }`
use_field_init_shorthand = true

# Forces let else blocks to always be their own line(s).
# Enforcing this helps readers scan all early returns of a function at a glance.
single_line_let_else_max_width = 0
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Copying my previous review comment from the last time you submitted this:

If we do decide to set this, I'd expect it to have the same value as single_line_if_else_max_width, I think.

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I disagree, for the reason exposed in the comment above.

I think

let foo = if x { y } else { z };

is fundamentally different from

let Some(foo) = x { y } else { return z };

and that, unlike the if else case, the else return case deserves to be spread out no matter its length.

In general, I think a control-flow-altering statement should always be on its own line.

(In theory you can do a single line if x { y } else { return z }, but only by treating the return statement as an expression, which is rare in practice.)

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Thank you for providing reasoning. I'm not completely sure I agree; for one thing, no style guide would ever have the formatting:

some_fallible_operation()
    ?
    .action()
    ?;

To be clear, my preference would just be to stick with the default, rather than matching the two at zero; I don't think it's a significant enough win, and IDEs can already highlight exit points for you in a much more complete manner

That being said, I'm not going to argue for it further; e.g. the Xilem repository which already has this set has literally no occurrences which would be formatted on a single line anyway.


# Commented out because it is still unstable, but works fine in practice.
# imports_granularity = "Module"

# END LINEBENDER RUSTFMT CONFIG
```

You may also want to occasionally use this unstable config:

```toml
# Groups imports in a predictable way: first core/alloc/std, then other crates, then the current crate.
group_imports = "StdExternalCrate"
```

We don't recommend it as a permanent config value even for nightly projects, because the way it reorders items [isn't always ideal](https://github.com/linebender/linebender.github.io/issues/87).
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Maybe "exports" rather than "items" here?

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I think "items" is fine for a short description.


## Markdown

In Markdown files, every paragraph should have one line per sentence.
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